Study of aromatic sulfide polymers: Poly(2,5‐thienylene sulfide)

Two methods of synthesis of poly(2,5‐thienylene sulfide) have been developed. The first of these is based on the uncatalyzed condensation of thiophene with sulfur chlorides and the second on the self‐condensation of 2‐chloro‐5‐thiophene thiol promoted by cuprous oxide in dimethylformamide. The polymers obtained by both methods are linear in structure and probably of low molecular weight. The polymer decomposes at 250–260°C. in air and under nitrogen. A study of molecular models suggests that steric hindrance may play an important part in the low thermal resistance of poly(2,5‐thienylene sulfide). Comparisons are drawn with the analogous poly(phenylene sulfide).